It's hard to tell these days whether the sands shift faster on the Tigris or on the Potomac. Four and a half years ago we invaded Iraq to disarm Saddam, or so we were told. When we found out Saddam had secretly gotten rid of his weapons of mass destruction, the justification for the invasion became to plant the seeds of democracy. Now, with intractable political gridlock in Baghdad, the reason it seems we're in Iraq is to promote a "tribal awakening"  unite Iraq's Shia and Sunni tribes in some grand tribal confederation. We're going to fight terrorism by turning the clock back to 7th century Arabia.

If I hadn't read it in Tuesday's White House press briefing, I would have taken the whole thing as a hoax. But indeed, on Tuesday Bush met with the head of the Islamic Supreme Council of Iraq, Abd al-Aziz Hakim, to discuss the "tribal awakening."

Never mind that the last thing Hakim wants to do is hand power over to the tribes, his real objective being to turn Iraq into a Shi'a Islamic republic. Or that Iraq's tribes are no more ready than any other Iraqis to share power, equitably divide Iraq's oil revenues, or compromise on any of the other issues that are causing Iraqis to kill each other.

I know what life raft Bush is clinging to. The Sunni Arab tribes in Anbar province have in fact turned against the insurgency, and, yes, brought down the level of violence. But that doesn't mean Fallujah has turned into Crawford, Texas. Nor have the bombings in Baghdad stopped, even if the tribes have helped walk Iraq back from the abyss.

The Bush Administration would like us to believe we picked up a new ally in the war on terrorism, that there's momentum on our side. In fact, the Administration has been so encouraged by the success in Anbar that it intends to use it as a template in Pakistan. In 2008, the Pentagon will nearly double the money it gives to the Frontier Corps, a Pakistani paramilitary force recruited from the tribes along the Afghan-Pakistani border. The Pentagon is hoping they will do what Pakistan's army couldn't, find bin Laden and drive the Taliban out into the open.

Before Bush puts on a burnoose and starts thinking he's Lawrence of Arabia, he needs to understand that Anbar's tribes came over to our side because they figured out that the only thing that stands between them and getting crushed by the Shi'a is our troops. They don't really care about our war on terrorism. He should also keep in mind that an estimated 40% or so of foreign fighters in Iraq are Saudis, another tribe that happens to be fighting on the wrong side. Tribes are tricky like that.

And then there's history, which the Iraqis can't seem to put behind them. The British tried to rule Iraq through the tribes and failed, spectacularly. They learned the hard lesson that Bedouin tribes are rented and never owned. They tend not to be there when you most need them. And they're certainly not going to substitute for the Iraqi state we destroyed in March 2003.

So maybe it's Bush who needs to put history behind him; the tribes can only be a band aid. As the old Persian proverb goes, "You can't draw water from a well with a rotten rope."

Robert Baer, a former CIA field officer assigned to the Middle East, is TIME.com's intelligence columnist and the author of See No Evil and, most recently, the novel Blow the House Down